I'm GB1, healer, and grinding is a problem since jinan mobs are too weak and nanchang mobs are 10 levels above me. The only place is CC, 3rd floor, but I get killed every 3 minutes and I have to run 10 minutes till I get there. Any help?
Go to CC and train there until you reach higher levels. Or you can try going to Superior version of Dungeon to train there. Mobs in Superior version of Dungeons are usually 10~15 levels higher than the Normal version. You can use 9 keys of normal version to exchange for 3 keys to Superior version of same Dungeon.
